This invention relates to inflation valve gauges for tires and the like, and is particularly suited for, but not limited to the landing gear of large aircraft which utilize a plurality of large volume tires operating at high pressures, often in excess of 100 psig.
In present day installations, the inner tube or the wheel is provided with a stem having a fluid passage for introducing air or other gas under pressure into the pressure chamber of the inner tube or tubeless tire or the like. A check valve is mounted in the stem for controlling fluid flow into and out of the pressure chamber. The tire is inflated by coupling a source of higher pressure at the outer end of the stem. The tire is deflated by manually moving the valve plunger of the check valve against the action of the valve spring. The pressure in the tire is measured by coupling a pressure gauge to the outer end of the stem, with the gauge including a member for engaging and depressing the valve stem. Tire inflation and tire pressure checking are performed as separate, sequential steps, which usually must be repeated several times in order to achieve the desired tire operating pressure.
In the inflation valve gauge of the present application, a continuously indicating pressure gauge is built into the stem, permitting continuous monitoring of tire pressure during tire inflation and permitting checking of tire pressure condition at any time without removal of the stem cap and application of a separate pressure gauge. The inflation valve gauge of the present application is directly substitutable for the conventional stem and is readily installed by deflating the tire, unscrewing the conventional stem, screwing in the gauge of the present application, and inflating the tire.
Accordingly, it is an object of the present invention to provide a new and improved inflation valve gauge particularly suited for continuously monitoring tire pressure both during and subsequent to tire inflation, and one which is directly substitutable for conventional stems.
A further object of the present invention is to provide an inflation valve gauge utilizing a special helically coiled highly sensitive Bourdon type of gauge tube disposed between confronting walls so spaced that the guage tube normally clears the walls but is movable within its elastic limit into fully supported contact therewith when subjected to mechanical stresses such as that produced by high centrifugal stress and high acceleration or deceleration stress; the gauge tube, upon relief of such mechanical stress, returning to its initial condition without change in the accuracy of the indicated or monitored pressure.
Other objects, advantages, features and results will more fully appear in the course of the following description, where the drawing merely shows and the description merely describes preferred embodiments of the present invention which are given by way of illustration or example.